SqlAGReplica: fix SeedingMode check in Test-TargetResource

[cai-n]

Pull Request (PR) description

• SqlAG
  • Fix SeedingMode existence condition as AvailabilityReplicaSeedingMode is an enum.
• SqlAGReplica
  • Fix SeedingMode existence condition as AvailabilityReplicaSeedingMode is an enum.

This Pull Request (PR) fixes the following issues

None

Task list

• Added an entry to the change log under the Unreleased section of the
  file CHANGELOG.md. Entry should say what was changed and how that
  affects users (if applicable), and reference the issue being resolved
  (if applicable).
• Resource documentation updated in the resource's README.md.
• Resource parameter descriptions updated in schema.mof.
• Comment-based help updated, including parameter descriptions.
• Localization strings updated.
• Examples updated.
• Unit tests updated. See DSC Community Testing Guidelines.
• Integration tests updated (where possible). See DSC Community Testing Guidelines.
• Code changes adheres to DSC Community Style Guidelines.

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This change is 

[johlju]

@cai-n Since there is no issue linked to this PR, can you explain the need for this change and why it is necessary in your scenario? 🙂

[Copilot]

Pull Request Overview

This pull request updates the changelog to document fixes for the SeedingMode existence condition in both SqlAG and SqlAGReplica.

• Updated changelog entry for SqlAG to clarify the fix.
• Updated changelog entry for SqlAGReplica to clarify the fix.

Files not reviewed (4)

• source/DSCResources/DSC_SqlAG/DSC_SqlAG.psm1: Language not supported
• source/DSCResources/DSC_SqlAGReplica/DSC_SqlAGReplica.psm1: Language not supported
• tests/Unit/DSC_SqlAG.Tests.ps1: Language not supported
• tests/Unit/DSC_SqlAGReplica.Tests.ps1: Language not supported

[cai-n]

Hi, I was trying to change the a replica's seeding mode from automatic to manual and noticed that it didn't update the replica, but it worked if it was the other way around

[johlju]

Thank you. Have you tested that your change actually makes it possible to switch between both?

Also, unrelated to your PR and does need to be resolved here, but looking at this now, isn't this a bug:

SqlServerDsc/source/DSCResources/DSC_SqlAG/DSC_SqlAG.psm1

Line 254 in 83c8385

$SeedingMode = 'Manual',

If a Availability Group has Automatic as a seeding mode, and if the user does not provide the Seeding Mode parameter in the configuration, then the resource will change to Manual on the Availability Group because of the default value that will be used and enforced. 🤔

[cai-n]

I've tried to change it from manual to automatic and back to manual and it updated correctly.
About the default, I think this line should skip the parameter check if it's not in the configuration and not trigger the update:

SqlServerDsc/source/DSCResources/DSC_SqlAG/DSC_SqlAG.psm1

Line 774 in 83c8385

foreach ( $parameter in $PSBoundParameters.GetEnumerator() )

[johlju]

You are correct with the default value. Thank you. This is also handled with $submittedParameter in 'Set' if it would be called separately. So it seems that is not an issue. Cool, no need for an issue for that then. 🙂

SqlServerDsc/source/DSCResources/DSC_SqlAG/DSC_SqlAG.psm1

Line 530 in 83c8385

if ( ( $submittedParameters -contains 'SeedingMode' ) -and ( $sqlMajorVersion -ge 13 ) -and ( $SeedingMode -ne $availabilityGroup.AvailabilityReplicas[$serverObject.DomainInstanceName].SeedingMode ) )

[johlju]

Reviewed 5 of 5 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @cai-n)

[johlju]

Waiting for the tests to pass, then I merge.

[johlju]

@cai-n thank you for this! 🙇‍♂️